Ridge Preservation in Molar Sites Comparing Xenograft Versus Mineralized Freeze-dried Bone Allograft

Twenty-four patients in need of maxillary or mandibular molar extraction and subsequent implant placement were included and randomly assigned to a group; allograft or xenograft, plus a collagen membrane. Cone Beam Computed Tomographies were obtained after molar extraction and after five months. A bone sample was harvested at the time of implant placement and analysed by histomorphometry.

Inclusion criteria

• Adult patients, over 18 years old.
• In need of removal of a maxillary or mandibular molar first or second molar.
• The molars to be extracted had to be bordered by at least one tooth.
• The molars had to have a presence of > 2 mm of keratinized gingiva and three intact bony walls.
• A dehiscence on the fourth wall, if any, had to be equal or less than 2 mm in height.
• Only one extraction per patient was accepted.

Exclusion criteria

• Acute periodontal or periapical infection.
• Pregnancy or lactancy.
• Smokers of more than 10 cigarettes per day.
• Previous adverse reactions to the biomaterials used in the study.
• Metabolic diseases affecting the mechanism of bone remodelling.
• Medications or treatments taken in the last twelve months and known to affect bone "turnover".
• Patients with poor plaque control -more than 20% (O'Leary, Drake, Naylor, 1972).
• Patients with absence of periodontal health maintenance or postoperative recommendations compliance.